JCO: Active surveillance reasonable for low-risk prostate cancer
Researchers have become increasingly concerned that treatment of recently diagnosed prostate cancer might not be the optimal standard of care, primarily because recent studies have suggested that as many as 48 prostate cancer patients must be treated in order to save one additional life.
As a majority of men diagnosed with prostate cancer are over the age of 65 and present with low- to moderate-risk disease, physicians have increasingly looked to active surveillance as an alternative course to intervention, resorting to treatment if the cancer is eventually restaged.
Since 1995, physicians at Johns Hopkins Hospital in Baltimore have counseled low- to moderate-risk men on active surveillance, enrolling a total of 769 patients in the program. The median age of all patients was 66 years with a median follow-up of 2.7 years (ranging up to 15 years).
Seventy-eight percent of patients met all criteria for very-low-risk cancer according to National Comprehensive Cancer Network-endorsed standards: clinical stage T1c disease, prostate-specific antigen (PSA) density less than 0.15 ng/mL, Gleason score less than or equal to 6, two or fewer biopsy cores with cancer and a maximum of 50 percent involvement of any core with cancer.
As of March 2010, 54 percent of the men remained on active surveillance, while 33 percent had undergone curative intervention, in all but 20 of whom biopsy had resulted in reclassification of the cancer. No patients died over the course of the study from prostate cancer, while 82 of 769 were lost to follow-up.
Prostate-specific antigen (PSA) levels, percent free PSA, PSA density (PSAD) and year of diagnosis significantly predicted which patients would undergo treatment, which included radical prostatectomy (96 of 192 delayed interventions) and radiation therapy (96 interventions).
“Promisingly, our data reveal that the great majority of men on surveillance were compliant with our follow-up biopsy regimen,” observed Jeffrey J. Tosoian, MD, and colleagues from the James Buchanan Brady Urological Institute and Johns Hopkins Hospital and School of Medicine in Baltimore. Compliance with annual surveillance biopsies over 12 years of follow-up was 89 percent.
Among the 514 patients who did not undergo treatment and the 255 who underwent radical prostatectomy or radiation either initially or eventually, the median PSA level in the untreated group was 4.7 ng/mL, compared with 5.0 ng/mL in the treatment group. Median percent free PSA at diagnosis was 16.2 for the treatment group and 18.0 for the surveillance group, while PSA density was 0.1 ng/mL greater in the treatment group. All results reached significance.
Patients experienced a median of 6.5 years on active surveillance without requiring radiotherapy or prostatectomy. The probabilities of a patient not requiring either curative intervention two, five and 10 years after diagnosis were 81 percent, 59 percent and 41 percent, respectively.
The authors also found that younger patients (median age 63) were significantly more likely to undergo surgery than their 67-year old counterparts.
On the basis of their findings, Tosoian and co-authors argued that “Limiting surveillance to patients with the lowest risk category of disease may reduce the incidence of adverse outcomes.”
The researchers pointed out that their use of biochemical recurrence after treatment as a proxy for long-term outcomes should be interpreted with caution.
“In conclusion, recognizing the limitations of predicting outcomes in men diagnosed with prostate cancer today, active surveillance with curative intent appears to be a reasonable alternative to immediate intervention for carefully selected older men,” Tosoian and colleagues wrote. They maintained, though, that “patients considering surveillance should be counseled on the possibility that delayed intervention may compromise the opportunity for cure in some cases.”